Image data, such as digital video data, because of the large data size thereof, is typically compression encoded in a predetermined method and transmitted and/or recorded on a recording medium. Currently, MPEG 2 (Moving Picture Experts Group 2) is known as a standard method of compression encoding of digital video signal. In accordance with MPEG 2, compression encoding process is performed using DCT (Discrete Cosine Transform) and motion correction, and further variable length coding is used to increase data compression rate.
In accordance with the encoding method for compression encoding data using variable length coding, like MPEG 2, the bit rate of the encoded data can become different from frame to frame. In the MPEG 2, an encoding bit rate of a frame to be encoded next is determined, and bit rate control is performed based on the determined bit rate when that frame is actually encoded.
Patent Document 1 discloses a technique in which a pre-encoding process for predicting an amount of generated code is performed prior to actual encoding, and the amount of code is appropriately controlled based on the results of the pre-encoding process.    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-359853